摘要
热电偶在温控系统中得到了广泛应用,但在实际测温过程中对热电偶的冷端补偿是必不可少的。分析了几种常用的热电偶冷端补偿方法的优缺点,根据1N4148在恒流条件下其管压降与温度的线性关系设计了一种基于PN结的热电偶冷端补偿电路,该补偿方法具有成本低、精度高、通用性强等优点,该电路可以对不同型号的热电偶进行冷端补偿,同时具有断偶检测功能。对E型热电偶进行了冷端补偿试验,结果表明,该补偿电路对热电偶冷端补偿后使得温度偏差≤1℃。
The thermocouple had been widely used in the temperature control system,but the cold junction compensation circuit must be used in actual application.The advantages and disadvantages of the several thermocouple cold junction compensation methods were described in this article,the relationship between the 1N4148＇s Forward Voltage and Junction Temperature is linear when the constant current flows the diode,according to the relationship,a thermocouple cold junction compensation circuit based on the PN junction was designed,which was low cost,high accuracy and strong universal,and it can compensate different types of thermocouple,the circuit also had the dual function of thermocouple＇s rupture detection.At last have a cold junction compensation test to the E-type thermocouple,and the results show that the thermocouple temperature measurement error ≤1 ℃ after using the designed compensation circuits.
出处
《电子测量技术》
2010年第11期10-13,共4页
Electronic Measurement Technology
关键词
热电偶
冷端补偿
PN结
恒流源
断偶检测
thermocouple
cold junction compensation
PN junction
constant current source
thermocouple＇s rupture detection
